This invention relates to optical phase scanning devices using an acousto-optical beam deflector, and more particularly, to scanning optical microscopes using a single laser beam.
The scanning optical microscope (SOM) has progressed to a stage where it constitutes a very powerful non-destructive examination tool. However, the classic design, which responds primarily to the intensity of light, experiences difficulties in producing high contrast images when examining objects showing small scale topography or refractive index variation. Various techniques to overcome this problem have been reported.
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In the majority of these prior art microscopes, the imaging is performed by extracting the phase information imposed on the interrogating beam. We have devised a new technique which results in an optical differential amplitude image, and thus substantially enhances the contrast.